Image sensors, and in particular Back Side Illumination (BSI) image sensors are becoming increasingly popular and used in a variety of applications. As is the trend with integrated circuit technology, the trend is toward smaller and smaller features for image sensors, to allow for lower cost and greater packing density. When pixels pitch scale down to the sub micrometer range, the photodiode area is limited and thus it becomes difficult to maintain the performance such as Signal to Noise Ratio (SNR), Quantum Efficiency (QE), sensitivity, and the like.
Elevated photodiodes may overcome some shortcomings in conventional structures and methods for making such structures. Specific process tuning is needed, however, for so-called elevated photodiodes, and the same would be constrained by Application Specific Integrated Circuit (ASIC) process conditions.